Expert: Martin Meyer - 5/20/2009

Question
Dear Mr. Meyer:

I have a mantel clock with a Hermle 340-020A movement (the one with the moon phase), when I wind it, the clock start to get faster for the first two days (it goes like 15 to 20 minutes ahead), then it starts to slow down until it stabilizes, I once send it for repairs and the clock was running ok for the first six months but now it is working wrong again. I would like to have your expert advice.

Thanks.

Answer
Hi Luis,

It is extremely unusual for a clock to run fast, then slow down after a couple days. I can only offer a few possible explanations for this behavior. First, make sure that you are winding all three mainsprings all the way, as far as they will go. Secondly, it is possible that the mainspring is worn out. Either of these things could cause the clock to run for only two days. The fast running would have to be due to the clock being regulated much too fast. In other words, you could have two problems; first, the clock is regulated too fast, so it gains time when it runs, and second, it only runs for a brief period because the mainspring is underwound or worn out.

Other than those things, it is possible, but probably not as likely, that the movement is worn out, that is, its bearings are worn. This could cause the the balance wheel to barely rotate, which in turn could cause fast running. Then after a couple days, the same wear which caused the weak balance wheel rotation could cause the clock to stop altogether. In any case, this is an unusual problem which will probably require an actual examination by a clockmaker to resolve.  http://www.clockmasteronline.com